The present invention relates generally to internal combustion engines, and more particularly relates to techniques for sensing the position of a needle or poppet valve in order to maximize the efficiency of engine operation and reduce unwanted exhaust emissions.
The present invention is an improvement over that disclosed in my U.S. Pat. No. 4,386,522 issued June 7, 1983, the disclosure of which is hereby incorporated by reference. In my previous patent I disclosed a sensor for detecting the opening of a fuel injection means such as a needle injector, poppet valve or the like in fuel injection apparatus of an internal combustion engine, the sensor comprising a header of an electrically insulating material having opposed first and second surfaces, and plural conductive leads, each lead separately coupled to the first surface of the header. Sensing means, such as a Hall effect detector, is mounted upon the second surface of the header for detecting the magnectic field and changes therein responsive to movement of the fuel injection means (such as the needle valve or poppet valve) in an internal combustion engine. Metalization means between the first and second surfaces provide innerconnection between the leads and the sensor. The leads, header and detector are all encapsulated, and are dimensioned for insertion into and out of the passageway in fuel injection apparatus including the fuel injection means.
Although the invention disclosed in my U.S. Pat. No. 4,386,522 serves a useful purpose and overcomes many of the deficiencies of the prior art, the production or manufacture of the position sensor using a specially constructed ceramic header is relatively expensive and difficult to manufacture. Furthermore, each header requires separate handling during wire bonding and encapsulation further increasing its cost of production.